I have a wet/dry with a sump, the tank is drilled at the bottom on both corners. Returns and overlfows are not glued to the bulkheads. Recently while fiddling with the plumbing on one of my returns I accidently pulled it out of the bulkhead. The pump was on so no problem and I stuck the tube back into the bulkhead. I have a couple concerns. First, I use sand as substrate. I am wondering if I now have some sand particles trapped between the bulkhead and the base of the return tube. Second worry - Do return tubes every just pop out of their bulkheads? Seems there is quite a bit of force from the water being pumped up into the return, then hitting the 90 degree elbow at the top. Would some kind of check valve between the bulkhead and the pump be a good idea?

